1. Field of the Invention
The present invention relates to a method and apparatus for controlling a grinder having a spindle with a deflection sensor and a signal temperature-compensation function of the deflection sensor output.
2. Description of the Prior Art
A grinding apparatus in the prior art has simply a set of fixed points of adjusting the cutting condition, because all of the working conditions such as rough grinding, fine grinding, finishing grinding, etc., are determined based on the change of measurements of a workpiece.
However, in this case, it is not possible to grind a workpiece under an optimum grinding condition taking into account a variation of the cutting efficiency of a grinder. Because of this, it is not possible to improve beyond a certain level, the grinding accuracy which is measured in terms of circularity, cylindricality, surface roughness, etc., and the grinding work efficiency.
There is another grinder in which the cutting amount is controlled in response to an electric power consumed for grinding work by the grinding shaft. In this apparatus, a force component of the grinding resistance acting in the tangential direction relative to the grinding shaft (in a direction perpendicular to the cutting direction) is indirectly detected, and thereby the cutting speed is controlled and the cutting condition is changed.
However, in this case, a tangential force component of the grinding resistance is detected, notwithstanding detection of a normal force component of the grinding resistance which is said to be the most favorable way to determine the cutting efficiency of a grinder, and therefore it is not possible to sufficiently detect changes of the cutting efficiency of the grinder and thus it is difficult to control the grinding condition at its optimum.